Earthiness is a flavor defect deriving from careless, primitive processing that in some contexts may be seen as virtues. Some Harrar coffees sold in specialty stores may have a hint of wildness or earthiness to them. Roasters from Italy often like to include some earthy-tasting Brazilian coffees in their espresso blends. If a New Orleans blend is at all authentic it also should have some Brazilian wildness in it. If the earthy taste dominates to the point that the coffee tastes distinctly sour or harsh, this quality becomes a flavor defect; you won't find such coffees in specialty stores. Your Sumatran sample may have a hint of earthiness or mustiness to it, but it shouldn't.
Depending on who is doing the tasting, it can be a taste defect or a desirable exotic taste characterized by how intense the earthy taste in question is.
refers to a particular flavour sensation that comes from certain Indonesian coffees.
Gaminess or Wildness: These terms refer to the coffees that embody an off taste caused by carelessly processed natural coffee. The taste is not enough to be considered dirty, sour or harsh, just slightly "off".
An undesirable taste or odor resembling the odor of freshly uncovered earth; Usually due to molds.
Either a taste defect or a desirable exotic taste characteristic depending on who is doing the tasting and how intense the earthy taste in question is. Apparently earthiness is caused by literal contact of wet coffee with earth during drying. Indonesia coffee s from Sumatra, Sulawesi and Timor are particularly prone to display earthy tones.